The present invention relates in general to thermostats, and in particular to a new and useful time variable thermostat having a double arm construction. One arm which rides on set pins may have notches to eliminate the need for a heat anticipator which is normally required in a thermostat.
The present invention is an improvement over the thermostat disclosed in U.S. Pat. No. 4,180,789, granted to one of the present inventors (Martucci) on Dec. 25, 1979. That disclosure is incorporated here by reference.
Virtually all thermostats now known utilize a so-called "heat anticipator" which includes a heating element that is activated for artificially heating the temperature sensing part of the thermostat. Such heat anticipators are necessary due to the inherent insensitivity of the thermostat to distinguish temperature changes within two or three degrees. As reported in Consumer Reports Buying Guide 1979 and 1980, pages 112, 113, there are disadvantages to such anticipators.
Thermostats are also known which can control both heating and cooling units, however the broad temperature range required for both heating and cooling renders it difficult to utilize the time variable thermostat concept as set forth in the above identified patent, due to the straight arm for enjoining pins in the slots of the control disc.